- 30 Jun 2023
- Ken Elliott
- Avionics - BizAv
Diving below the surface of aircraft Communications, Navigation and Surveillance (CNS), aircraft cabin and connectivity technologies, Ken Elliott concludes his series with a review of peripheral avionics.Back to Articles
Drawing the line between mainstream and peripheral aircraft avionics is not straightforward, and the goal of this article is to delve into technologies that are outside of popular focus.
Consider ‘popular avionics’ as Communications, Navigation and Surveillance (CNS), cabin and connectivity technologies, including those systems either mandated or required to operate along certain routes. In contrast, consider peripheral avionics as systems either independent of, or those associated with mainstream avionics.
Figure 1 maps peripheral avionics against CNS, connectivity and cabin systems. Each group may include several categorized systems, and for each there may be multiple avionics manufacturers offering the same technology in different products.
Figure 1 - Map of Peripheral Avionics Against Private Jet CNS Connectivity and Cabin Systems
While system manufacturers increasingly integrate different technologies into single systems, there are still many sub- systems that are either optional or remain as separate avionics equipment.
Peripheral Communication: As the aviation industry gradually transitions from voice to data cockpit communications, it is important to consider that when adding communications beyond Satcom and Very High Frequency (with a frequency range of 118-136.995 MHz).
For aircraft operating globally, High Frequency (HF) communication with an operating range between 3-30 MHz, is used for communication and optional datalink (HFDL) over oceans, the poles and in remote regions.
HFDL is an integral part of Future Air Navigation (FANS), where position reporting is essential during operation along oceanic tracks and other routes.
The magic of HF is its ability to radiate signals following the circular surface of Earth by reflecting off the ionosphere, ensuring extremely long-range communication. Very High Frequency (VHF) signals, meanwhile, radiate in straight lines and are only useful for relatively short distances.
A good example of a modern HF with datalink is Collins Aerospace HF 9000, with its different bands of operation, fiber optics, solid state tuning and stored frequencies. The HF collaborates with the Communications Management Unit (CMU 4000) that manages all datalink, including ACARS, VDL Mode 2 and ATN-B1, as well as Selective Calling via the HF (Selcal).
Peripheral Navigation: Most current navigation is via Global Positioning Systems (GPS), Variable Omni Range (VOR), Distance Measuring Equipment (DME) and for airports, Instrument Landing Systems (ILS).
For Business Aviation, many airport approaches use a Wide Area Augmentation System (WAAS) and Required Navigation Procedures (RNP), including Authorization Required (AR), as with the new Honeywell procedure approved for Aspen, Colorado. However, peripheral navigation encompasses:
Low vision: Low vision technology is employed to assist and validate the close in approach and take-off. Only ten years prior, the use of this navigation technique was considered exotic, and apart from its standard fit to most Gulfstream aircraft was not widely embraced by Business Aviation.
Now, that is all in the past and airframe manufacturers are readily offering low visibility solutions. For those unfamiliar with low vision, it comes in several flavors:
- Muti-spectral sensor-based HUD systems for landing credit.
- Combined Vision Systems (CVS) using multiple sensing sources including synthetic vision, for potential landing credit.
The credits available to flight crews are an advance on the standard ILS of 200ft Decision Height (DH), with some at 150ft, some at 100ft, and advanced or future systems seeking 50ft or less.
The aircraft low vision systems, integrated for operational credit, are typically at the behest of the airframer and some of those are offered as an upgrade. This is also because the EFVS is so reliant on other aircraft information to ensure, amongst other tasks, that its Flight Path Vector (FPV) is precise at critical altitudes.
Equipment providers offering SVS and EFVS solutions include Collins Aerospace, Universal Avionics (Elbit Systems of America), Honeywell and Garmin. These providers offer their variable solutions to airframers on different aircraft types. Some will have limited flight credits and others, such as certain Gulfstream models, can use EFVS to land.
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